A liquid crystal cell of a liquid crystal display is formed by laminating two glass substrates, each of which is provided with an alignment film for guiding the alignment of the liquid crystal. Due to the DC blocking effect of the alignment film and the DC residual voltage caused by the movable ions in the liquid crystal cell, a defective display such as residual image occurs during the display of the liquid crystal display. To solve the defective display caused by the above reasons, the liquid crystal display generally adopts a driving mode of polarity inversion.
When the liquid crystal display adopts a driving mode of polarity inversion for display, a thin film transistor for controlling the loading of a pixel display signal presents a parasitic capacitance effect during charging and discharging, the parasitic capacitance effect will redistribute the charges and a voltage drop effect will occur, that is, to generate a so-called kick back voltage, so that the positive and negative polarity voltage of a source electrode voltage is asymmetry, which causes flicker.
Currently, the problem of flicker caused by the kick back voltage is solved by optimizing a common voltage value written into the LCD driving chip (a common voltage generation circuit provides a common voltage to the display based on the written value), the method is as follows:
S11, illuminating a panel after the attachment of a driving chip and a flexible circuit board, and testing a flicker value of the display panel under flicker pattern;
S12, minimizing the flicker value by regulating the value of the common voltage;
S13, writing into the driving chip the value of the common voltage applied when the flicker value is minimized.
However, the present inventor finds that the common voltage value obtained by the above method has the following problems during the final display: the flicker in the center region of the display panel is relatively small, while the flicker in the edge region is relatively severe; leading the flicker uniformity is poor and influencing the display effect.